I am not an engineer, though I had HO trains as a child. My limited understanding is that crumple zones are designed to absorb energy rather than transmit that energy elsewhere such as into the occupants of the vehicle. That energy is absorbed (dispersed) during the collapse of the panels. The energy (inertia) of the vehicle from being in motion to not being in motion (relative to the occupant) is dispersed and increases the time it takes to stop (or slow) the vehicle. As stated elsewhere in this thread by real engineers (I think), if those panels are not intact (i.e., no cracks) upon impact, the energy is not dispersed thus reducing the effectiveness of the crumple zone. If those panels are bulged or dented, their effectiveness is also reduced but not as much as if they were fractured. The question is, is the reduced effectiveness of the cracked or buldged panels sufficient to imperil the occupants' safety beyond the acceptable limits set by NHTSA. That question can only be answered by NHTSA and/or Toyota engineers. A second question is whether or not these defective panels are an anomoly or are they an inherent defect in the early (and later) designs. That is a statistical question that can only be answered by an analysis of the numbers of vehicles with and without the problem as time goes by. That statistical question can only be answered (precisely) by examining LOTs of vehicles. I am quite confident Toyota now or in the near future will be examining all FJC's that come in for service or other reasons. My question to the factory rep, would be, "Is Toyota directing the service departments (of the dealers because almost all FJC's are still under warranty) to examine, in detail, these panels?"
Has anyone asked that yet?
My guess is that Toyota has been doing this since day one. My second guess is that Toyota has determined it will not lift the curtain, admit this problem or take ownership of same until the numbers are irrefutable, if ever. The cost of resolving this problem is way too great for Toyota to take any quick action. When there are no new FJC's being sold by the dealers, Toyota will have made a decision to cut it's (future) losses. Nevertheless, the battle will be between Toyota and the NHTSA. Our duty is to provide NHTSA with the evidence it needs to resolve this from a safety standpoint. From a PR perspective, Toyota is very close to dropping the ball if it hasn't already.
Has anyone access to the sales figures? I still see them on the lots so I presume they are still selling them.
In a significant enough front-end collision, the crumple zones in our FJ's are gonna crumple whether they are bulged, cracked or perfectly straight.
QUOTE]
Please,
You are correct in the broad term that they are designed to crumple, they are designed as a complete piece working in sync so at the front the design is a little weaker/softer and so on to the stiffest/hardest part at the back.
Imagine compressing a spring its soft to start with hard at the end.
It is that absorption of energy that protects you and slowly decelerates you. It is the whole thing linked together that allows this. With it disconnected (cracked) or already starting to deform, you will get all the energy in one spot, (weakest link=crack bulge tear) In some instances it may not matter, but it does lessen the performance of the crumple zone. By how much we do not know, I bet Toyota will soon though.
I think we're sorta sayin' the same thing.
The idea is to confine as much of the damage to the front end of the vehicle thereby protecting the passenger compartment which is designed to remain intact. By design, the front end should absorb energy by being crushed. No argument there.
The question is, will a little crack in a paper thin body panel make a significant difference in how the vehicle performs in a crash and will the NHTSA get jazzed about it?
If this sheetmetal was insignificant, why would Toyota bother to engineer crumple zones into it? That's costing pennys, not saving them...
Didn't I just say the same thing in my post?
Quote:
DEEZUS previously said:
The manner in which the crumple zone fails must have some direct relationship to the impact that is observed on you and the rest of the vehicle. If they were so insignificant Toyota would not have put them there.
We're on the same page. And I'm not an engineer either.
One thing I'd like to point out relative to your comments is that back in the bad old days, before crumple zones, the problem was not that the front ends of cars were too soft. The problem was they were too hard.
Our little cracks and bulges could actually help protect us in a crash. Just something to think about.
You also said..."Also, I understand the idea about how insignificant the sheetmetal is. But I don't think the NHTSA will see it that way.
Doesn't that contradict this..."The manner in which the crumple zone fails must have some direct relationship to the impact that is observed on you and the rest of the vehicle. If they were so insignificant Toyota would not have put them there."
I don't know....this is all so aggravating and confusing...
These are from today. The new fender aprons and front clip are on and painted. I was talking to the shop manager ( he's not an engineer) and he thought the solution would be to box in the outer side of the apron. Older aprons were boxed in all the way to the front. The FJ's stops about 6-8 inches infront of the fire wall. About were the ripping is taking place. He also told me that replacing the aprons once is no problem, but doing it a second time is A LOT harder. Lets hope the Toyota engineers or Valky come up with an easy solution that does not require the removel of the new aprons. I do not really want to see my rig in this state again. The old parts have gone back to Toyota for study.
These are from today. The new fender aprons and front clip are on and painted. I was talking to the shop manager ( he's not an engineer) and he thought the solution would be to box in the outer side of the apron. Older aprons were boxed in all the way to the front. The FJ's stops about 6-8 inches infront of the fire wall. About were the ripping is taking place. He also told me that replacing the aprons once is no problem, but doing it a second time is A LOT harder. Lets hope the Toyota engineers or Valky come up with an easy solution that does not require the removel of the new aprons. I do not really want to see my rig in this state again. The old parts have gone back to Toyota for study.
Holy crap! Why the hell did they have to yank the whole dash? Did they have to drop a bunch of wiring harnesses to get the aprons off? Or maybe they need to weld against the firewall back in the sides there.
I could not deal with that. You're taking this so much better than I could. If my truck develops this problem and they try to tell me the solution involves removing the front body and dashboard I'm going to want a check for $10k, or a new truck. I know fastenings are getting better and all, but I just don't think that's going back together the way it came out of the factory.
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Black Cherry
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Nah MarkBNJ ... I would not worry too much about it not being factory spec once reassembled. I got T-Boned in my 3 day old 5 Series BMW and it was close to totaled. I nearly fainted when I saw the level to which the bodyshop had to rip that thing down. I had NO faith that they could get it back together. To top it off i was not a fan of the shop mgr. But when I got that thing back it was factory tight. I consider it better than new because half the car had been replaced so half of it was newer.
Bernd, stay optimistic. They will button it up tight I bet.
Bernd
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